1. Field of the Invention
The present invention relates to fruit- and nut-harvesting equipment, and more particularly to apparatus for shaking fruit and nuts from the limbs of trees.
2. Description of the Related Art
Mechanical devices for harvesting fruit and nuts from trees typically operate by gripping the tree trunk and imparting thereto a controlled, low-frequency vibration or shaking action. This operation dislodges the fruit or nuts, which are then collected and transported.
A typical tree-shaking apparatus includes two opposing clamp members that engage the tree trunk, and which are themselves driven by dual oscillation or vibration units. Because droppage occurs over the relatively wide area corresponding to the extent of the tree's foliage, suitable collection apparatus must span this area yet be conveniently transportable from tree to tree. Such apparatus should also include a local conveying assembly for drawing the harvest into a single container as it falls from the tree.
One common approach to collection is illustrated in U.S. Pat. Nos. 4,269,021, 3,623,308, 5,191,758, 5,123,238, and 1,626,068. In each of these patents a segmented, fan-shaped collection net, its panels canted to form a bowl, surrounds the tree so that falling fruit or nuts gather at the bottom of the net. From there it is transported to a bin by means of conveyors or the like. These arrangements are large and cumbersome, particulary when fully open, and can be difficult to maneuver into the precise position necessary for the net to properly encircle the tree. They must be fully opened before a tree is shaken and are ordinarily fully closed prior to transport to the next tree.
Another collection approach is set forth in U.S. Pat. No. 3,548,579, which discloses a two-part apparatus that encloses the tree from opposite sides as it is shaken. The fruit or nut harvest accumulates in opposing slack, flexible sheets that elevate and tilt when shaking is complete, causing the harvest to roll off onto a collection conveyor. This arrangement requires a relatively elaborate construction to provide the necessary snapping and tilting actions of the different components and to coordinate their interplay.